An image processing device that encodes image data including: an encoding unit which, with a small region line including, arrayed in the horizontal direction, small regions obtained by dividing large regions arrayed in the vertical direction of an image, performs encoding of image data of the large region, advancing the encoding order of small regions in the same order as a scan order, and advancing the encoding order of small region lines in an order different from the scan order; and a control unit that controls the encoding unit to encode in accordance with a state of a left small region situated at a left periphery of a small region to be processed, and a state of a lower small region situated at a lower periphery of the small region to be processed. The device suppresses deterioration in encoding efficiency due to high speed image encoding.